GTX 1070 SLI vs GTX 1070ti

So obviously GPU prices are outrageous right now, but in about 6 months to a year when the market normalizes I want to upgrade my GPU. Currently I have an EVGA GTX 1070 super clocked, but would it be worth it to get a second GTX 1070 and run it in SLI or just to get a GTX 1070ti?

On PC, I play Far Cry 3 /4 (I will probably get 5), Skyrim Special Edition, Witcher 3, and Dragon Age: Inquisition just to name of the few and as you can see, most of these games are pretty graphically demanding, especially when modded. Primarily I am a 1080p gamer, but ever since I got my 4K TV, I have linked up my rig to my TV and I have been gaming between 2K and 1440p with pretty great results.